This invention relates to operation apparatus which is operable for opening and maintaining the flow of fuel upon actuation of the ignition operation apparatus in a gas appliance such as a gas room heater.
There has been hitherto proposed operation apparatus having an operation lever which is movable from a starting end position to a final end position by pushing it against the action of a return spring, and a lock member which is operable to stop the operation lever at an intermediate position during returning movement of the operation lever caused by the action of the return spring. Used in a gas appliance, the operation lever serves to control to open and close a gas valve interposed in a gas passage connected to a gas burner, and an ignition switch for operating an ignition plug provided near the burner, so that there may be obtained a valve closed condition at the starting end position of the operation lever, a valve open and an ignition switch closed condition at the final end position of the lever, and a valve open condition at the intermediate position of the lever. This operation apparatus is inconvenient, however, in that the course of pushing operation thereof, if the operation lever is released from pushing before reaching the final end position, that is, before completion of the pushing operation thereof, the operation lever member is then stopped by the lock member at the intermediate position thereof, that is, in the valve open condition thereof, and thus the burner is supplied with gas under the condition that the burner is not yet ignited.
According to the present invention, there is provided operation apparatus comprising an operation member which is movable from a starting position to a final position against spring-action, and a lock member which is operable to stop the operation member at an intermediate position during return movement of the operation member caused by said spring-action, this lock member being normally kept in an inoperative condition in which it is ineffective to stop the operation member, and being brought into an operative condition in which it is effective to stop the operation member only when the operation member is first moved to its final position. Thus, in this apparatus the operation member will be stopped at its intermediate position when returning thereto under the action of the return spring only if the member was previously moved all the way to its final end position.